Throughout its 40 plus year history Earth Day has been a rallying point for millions of personal acts intended to help save the environment.
It has sparked rallies and marches, demonstrations and parades, contests and car washes, and with the aid of the Internet and social media tools it has become a global moment in time to signal the importance of living more sustainably.
Earth Day street and stream clean ups, recycling drives, letter writing campaigns and similar calls to reduce, reuse, and recycle have shaped the minds of two generations of eco-conscious youth on the importance of protecting our natural environment.
And of course, it has sparked endless political speeches with buttons, banners and policy oriented statements. Even businesses have been involved, not only through sponsorships of this annual celebration, but also by cutting wastage, lowering the energy use, and changing the way they operate to become more ecologically balanced.
This year's theme for Earth Day 2011 is "A Billion Acts of Green: Personal, organizational and corporate pledges to live and act sustainably".
Like its more recent companion Earth Hour, Earth Day has shown that for one brief moment, we can come together in common cause to make a difference, to show that change is indeed possible.

Converting forms of public transportation over to green technology is a great way of reducing the carbon emissions in a particular metropolitan area. To this effect, many cities around the world have invested in buses that utilize either hybrid systems or fully renewable fuel sources. London in particular has been working on hybridizing their buses, but now has turned their attention to their famous black cabs.

Some 21,000 succulents call the roof of New York City's Con Edison's three-story Learning Center in Long Island City, Queens. The facility - some pales in comparison to the 2.5 living roof atop the Postal service facility in mid-town Manhattan. Meanwhile Chicago, the city that plays host to more green roofs than any other US City, added some 600,000 square feet of green roofs last year bringing their total coverage to a whopping 7 million square feet according to a December Yale Environment 360 article. The city of Toronto even went so far as to mandate that new buildings above a certain size will have to cover at least 60% of their roofs with vegetation.

Tanzanian President Jakaya Kikwete directly contradicted his own government's study by claiming that a planned highway in the Serengeti National Park will not be the environmental disaster conservationists and scientists are claiming it to be.

Creating new well-paying jobs to spur the economic recovery remains a central concern globally and in the US. The Great Recession has left many professionals and their families struggling to make ends meet for over two years. This jobless recovery is likely to be the longest recovery since the Great Depression. Furthermore, the convergence of automation and globalization have resulted in permanent changes in jobs across many industries. For instance, manufacturing and construction jobs are today more technical and requiring more education than 20 years ago. Due to the same pressure of automation and globalization, middle management jobs are also disappearing.

The government of Italy has become the first in the European Union to outlaw the use of plastic bags by all retailers, signaling a large shift in a country which uses over 20 billion bags per year (400 per person) — an amount equal to 25% of the total produced and used in the entire EU.

Denmark, like, Germany, her neighbor to the south, is a country that takes renewable energy seriously. The wind energy industry alone in Denmark is booming with companies like Vestas and Siemens Wind Power both having production facilities and bases of operation on Danish soil. Denmark's own wind based energy also grows exponentially each year leaving many optimistic that the nation might be one of the few who can achieve 100% renewable energy in the next several decades.

From wind turbines to solar photovoltaic cells, sustainable business ventures have produced a plethora of well-tested methods for converting renewable energy into electricity. Though much remains to be done when it comes to actually replacing coal and other fossil fuel-based electricity with a clean energy grid, there is little doubt that the technology to do so exists. A far greater challenge has been finding a truly renewable and sustainable energy source capable of replacing the petroleum-based liquid fuels used to power motor vehicles and aircraft. But scientists at the California Institute of Technology may finally be closing in on a solution.

This past weekend at the second annual Japan-Arab Economic Forum, the governments of Japan and Tunisia formally sealed a deal to collaborate on a sustainable business project that takes advantage of Tunisia's ample solar resources. Together the two countries will be building a solar power plant in the Sahara desert, which is rapidly becoming a hot spot for some of the most innovative solar power projects in the world.